This was originally an issue by @imjohnbo in `github/special-projects`, a private repository:

> ## Summary
>
> Today, content is pasted into GitHub comments (issues, PRs, discussions, etc) as plaintext, except for a [few special cases](https://github.com/github/paste-markdown#paste-markdown-objects) managed by [`@github/paste-markdown`](https://github.com/github/paste-markdown).
>
> It's a laborious process to add formatting and links of the copy source back into the paste target. For example:
> - Copying/pasting part of a GitHub comment into a GitHub comment box – maybe in a different issue – in order to reply to it
> - Copying/pasting part of a Google Doc shared with a customer into a GitHub comment box in order to add context to it
> - ...
>
> This issue would build on https://github.com/github/special-projects/issues/679 and investigate adding Slack-like paste functionality for the features GitHub developers care about, including:
>
> | name | html | markdown |
> |-----------------|----------------|----------------------|
> | headings | `

`, `

`... | `#`, `##`, etc. |
> | inline code | `` | \``code`\` |
> | code block | `

`    |         \`\`\``code`\`\`\`             |

> | bold            |    ``    |         \*\***bold**\*\*             |

> | italics         |   ``  |             \**italics*\*           |

> | ordered lists   |    `
`     |          1. item            |

> | unordered lists |   `
`       |      - item                |

> | task lists      | ?              | - [x] completed item |

> | quotes          |  `blockquote` |  > a long quote                    |

> 

> ## Example

> 

> This Google Doc:

> 


> 

> 

> 

> is pasted as:

> 

> ```

> Big Heading

> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris eleifend consectetur nisl, vel vestibulum odio mattis sit amet. Integer vehicula rhoncus augue, eu congue magna porttitor eget.

> Medium Heading

> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris eleifend consectetur nisl, vel vestibulum odio mattis sit amet. Integer vehicula rhoncus augue, eu congue magna porttitor eget.

> Small Heading

> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris eleifend consectetur nisl, vel vestibulum odio mattis sit amet. Integer vehicula rhoncus augue, eu congue magna porttitor eget.

> ```

> 

> when I would like it to be:

> ```

> # Big Heading

> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris eleifend consectetur nisl, vel vestibulum odio mattis sit amet. Integer vehicula rhoncus augue, eu congue magna porttitor eget.

> ## Medium Heading

> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris eleifend consectetur nisl, vel vestibulum odio mattis sit amet. Integer vehicula rhoncus augue, eu congue magna porttitor eget.

> ### Small Heading

> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris eleifend consectetur nisl, vel vestibulum odio mattis sit amet. Integer vehicula rhoncus augue, eu congue magna porttitor eget.

> ```

> 

> ## Spike

> 

> I started [a spike](https://github.com/imjohnbo/paste-markdown/tree/imjohnbo/html-to-markdown) over the weekend which allows for this:

> 

> ![paste](https://user-images.githubusercontent.com/2993937/150845376-8e6ac27d-01c1-4ab9-b1b5-db05bbede328.gif)

> 

> 

> ## Other

> 

> - [Pasteboard Viewer](https://apps.apple.com/us/app/pasteboard-viewer/id1499215709?mt=12) helps understand what's in the macOS clipboard

> - Here is a [Google Doc](https://docs.google.com/document/d/1dRgAa3MLK6U0HjFnvDXBP-gjdSCCatgCVDe89KPqnz8/edit?usp=sharing) with some test cases for convenience ❇️ 

Review the html-to-markdown spike and the linked Google Doc test cases first. Compare existing paste-markdown behavior with the listed HTML elements and define coverage for headings, code, emphasis, lists, and quotes; done means those clipboard inputs produce the intended Markdown without regressing existing special cases.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.